At present, the Universal Terrestrial Radio Access Network (UTRAN for short) includes a base station (Node B) and a Radio Network Controller (RNC for short), and a corresponding Core Network (CN for short) includes: a Home Subscriber Server (HSS for short), a Mobile Switching Centre Server (MSC Server for short) and a serving General Packet Radio Service (GPRS) Serving GPRS Support Node (SGSN for short) etc. The Evolved Universal Terrestrial Radio Access Network (E-UTRAN for short) includes an evolved NodeB (eNB), and a corresponding core network includes a Home Subscriber Server (HSS for short) and a Mobile Management Entity (MME for short) etc.
In order to reduce the cost and complexity of manual drive test by a carrier using a dedicated device, the Third Generation Partnership Projects (3GPP for short) organization begins to introduce a Minimization of Drive Test (MDT for short) function in Release-10 of the UTRAN and E-UTRAN systems. The MDT function collects a measurement report automatically using a User Equipment (UE for short), reports the measurement report to the Radio Access Network (RAN for short, for the UTRAN system, the RAN refers to RNC, and for the E-UTRAN system, the RAN refers to eNB) through control plane signaling, and reports the measurement report to a Trace Collection entity (Entity TCE for short) of the Operation And Maintenance (OAM for short) through the RAN. The application scenarios of the MDT primarily include aspects such as coverage optimization, capacity optimization, mobility optimization, public channel parameter optimization etc.
The MDT supports Management based MDT and Signaling based MDT. Taking the E-UTRAN system as an example, the process of activating the Management based MDT is generally a process that the OAM transmits a message to the eNB to activate MDT measurements of some UEs, and the eNB selects a UE according to the received area information, and transmits the MDT configuration information to the selected UE; while the process of activating the signaling based MDT is generally a process that the OAM transmits a message to the HSS to activate MDT measurement of a certain UE, the HSS transmits the MDT configuration information of the UE to the MME, the MME transmits the MDT configuration information of the UE to the eNB, and the eNB finally transmits the MDT configuration information to the UE. The Signaling based MDT generally designates a certain UE using an International Mobile Subscriber identity (IMSI for short) or an International Mobile Station Equipment Identity (IMEI for short), and sometimes will limit the selection of the UE with the addition of the area information.
The UE may perform MDT in the connected state and the idle state, wherein, the MDT performed in the connected state is referred to as immediate MDT, and the MDT performed in the idle state is referred to as a logged MDT. There may be two kinds of independent configuration information configured on the UE at the same time, including immediate MDT configuration information and logged MDT configuration information. Wherein, the immediate MDT configuration information is used to instruct the UE to measure and report the immediate MDT, and the logged MDT configuration information is used to instruct the UE to measure and store the logged MDT Both kinds of MDT configuration information are configured by the network side for the UE when the UE is in a connected state. The immediate MDT refers to a process that the UE in a connected state measures the MDT according to the received immediate MDT configuration information and reports the measurement report to the RAN in time, and the RAN reports it to the TCE; and the logged MDT refers to a process that the UE in an idle state measures the MDT according to the received logged MDT configuration information, stores the obtained measurement report, and reports the measurement report to the RAN until the UE enters a connected state later, and the RAN reports it to the TCE.
At present, for the two different measurement types including immediate MDT and logged MDT, the contents included in corresponding MDT configuration information are also different. Two kinds of configuration information include an MDT applicable range, an available cell list or Time Advance (TA) list, flag information of the UE (only applicable for UE based track in the UMTS) and MDT measurement contents. At the same time, the MDT-allowable Public Land Mobile Network (PLMN) list information may be added in both kinds of MDT configuration information. For the immediate MDT configuration information, it further needs to include a report trigger event, a report interval and a report number; and for the logged MDT configuration information, it further needs to include a logged report interval and logged configuration duration.
In actual networking, the network sharing enables the carriers to manage respective parts of their own flexibly while constructing a communication network cooperatively, thus largely shortening the construction period of the network, and largely reducing the Total Operating Cost (TCO). At the same time, the network sharing may facilitate resource optimization configuration, avoid repeated construction, and implement the maintenance and increment of the assets. Therefore, the network sharing has become a very important issue in the network construction.
There are many implementation methods for network sharing. One is access network sharing, i.e., multiple carriers share the same RAN in the sharing area, but use the core networks and the service networks independently. As shown in FIG. 1, the carrier A and carrier B may share the RAN provided by the RAN carrier. While in the process of MDT management and maintenance, the carriers want to have the benefit of the function in a network equivalent to the Home Public Land Mobile Network (HPLMN), so as to better collect the network information for network optimization. The equivalent network here may refer to an Equivalent Home PLMN (EHPLMN), or may also be a PLMN selected by a user during roaming and belonging to the same carrier and having the same national code as the HPLMN, which may be referred to as a Visited PLMN (VPLMN).
As long as the UE is located in a PLMN allowing MDT measurement, the UE may be selected to implement a task of MDT measurement. In the current handover process, as long as the UE does not perform an inter-PLMN handover, the immediate MDT configuration information may be transferred during the handover. If the UE performs an inter-PLMN handover, the immediate MDT configuration information of the UE needs to be deactivated, thus resulting in that the UE can not perform the immediate MDT measurement due to lacking of corresponding immediate MDT configuration information, even the UE is handed over to an EPLMN network supporting the mode of signaling based MDT.